Patent GB-205169-A (GB)
Title: Improved page-printing telegraph machine
IPC: H04L17/22
Filed: 1922-07-10
Abstract: 205,169. Murray, D. July 10, 1922. Electric type-lever mechanism. -Relates to an improved form of the page - printing telegraph described d in Specification 26918/08, with a view to economy of time so that the machine may work at high speeds, the principal feature being that the printer is mechanically operated by spring- stored power derived from a power shaft and under control of six trigger magnets (five selecting and one printing), power magnets and electrical contacts being avoided. Other features are the provision of an automatic blanking-feed or long vertical move. ment to feed a new page or blank into position, and arranging that carriage - returning mechanism automatically brings in line-spacing mechanism to avoid printing taking place on top of words already printed, but allowing the carriage-returning mechanism to be operated independently. The machine is designed mainly for use on multiplex circuits with distributor in the usual way. Slotted selector plates 2 are held to the right, Fig. 1. by pawls 38, Figs. 2 and 4, attached to the armatures of corresponding selector magnets 3 ... 7 selectively energized from the distributor to release the pawls and allow the selected plates to move to the left under spring action. Printing magnet 8 then receives an impulse from the distributor and a plate 50 carried by its armature 9 is moved to allow a cam-shaft 10 to be clutched at 11 to a continuouslyrunning shaft 12, and to make one revolution. A cam 16 allows a bar 18 to be moved so that latches 21 rest against the plates 2, the selected latch entering aligned slots and moving a corresponding hook 23 into the path of a universal striker bar 24, carried by arms 25 pivoted at 20. A printing cam 13 acting on a lever 26 then depresses bar 24 and the selected hook 23 so that the corresponding type-lever 33 pivoted on a curved rod 31 is raised by means of a lever 28 and link 29, the selected type striking against a platen 32. Immediately after a hook 23 has been engaged by bar 24, a lever 41 operated from a cam 14 returns the selector plates to initial position. It is necessary that the trip mechanism shall provide a secure lock, and, whilst being sensitive so as to be released by a brief impulse in the printing magnet 8, shall not be released by the vibrations of the printer. The clutch 11 is thrown into engagement by a spring, and is held out of engagement by a pawl 46. Secured to spindle of pawl 46 is a projection 49 having a bevelled surface engaged by a corresponding bevel on a detent 47 held lightly by a spring 51. Behind a heel on detent 47 is a blade 50 fixed to. the armature of magnet 8. A printing impulse moves blade 50 to release member 47, which is thereupon thrown out of engagement by the action of a strong spring 154 which moves members 46, 49 to the release position, allowing clutch 11 to engage. The required sensitiveness is obtained by selection of the angle for the bevel of members 47, 49. At completion of the revolution of camshaft 10, a tooth 170 disengages the clutch and restores members 46, 47, 49 to the engaged position, at the same time storing power in the clutch-spring and spring 154. Trip mechanisms used elsewhere in the printer as indicated below are similar in principle, and show only modifications in design to adapt them to their special functions. To prevent printing by the printing impulse when no selecting impulses are being received, a latch 42 prevents movement of the blade 50, the latch being disengaged through a lever 45 on operation of any of the selector plates. Case-shift mechanism.-The type-lever basket 33 is raised by a lever 36 selectively operated by one of the hooks 23, and retained by a catch, the catch being released to lower the basket by selective operation of another hook 23. Paper-carriages. - The carriage slides on a square spindle 53 passing through the platen 32, and supported on hollow brackets 54, 55. Rotation of the platen is effected by mechanisms not carried by the carriage, but housed in the brackets, and operating to rotate the spindle 53 as described below. Letter-spacing and carriage-returning mechanisms.-A spacing cam 15 on shaft 10 raises a lever 70 and a member 72 pivoted thereon, the latter engaging the lower end of a rod 74 so that a lever 75 is tilted, and a toothed pawl 68 cooperates with a ratchet to move the carriage one letterspace to the right, Fig. 3. The carriage is retained by a detent 69. At the same time a pivoted arm 78 is raised, and retained by trip members 82, 84, thus storing power in a spring 80. To prevent spacing when the ' erase ' signal is received, the selected latch operates to move member 72 from under the rod 74, which is therefore not affected. Carriage-return is effected on receipt of a predetermined signal selecting latch 159, Fig. 1, the inward movement of which moves member 84 of the trip mechanism. The spring 80 then depresses arm 78, and with it a plate 86 adapted to draw the pawls 68, 69 out of engagement with the carriage ratchet. Spring drum 64 and cord 65 then return the carriage, which is cushioned by a lever 66 and pneumatic device 67. Plate 86 is held depressed by a catch 87 released when the carriage return is completed. Line-spacing mechanism.-The spindle 53 and platen 32 are rotated through pawl and ratchet wheel 57. A lever 92 is moved by cam 17 to raise a lever 93 on a spindle 96. This spindle extends along bracket 54 and has an arm 97 extending into the bracket and connected to a spring (not shown) in which power is stored bv the above movement. Lever 93 is retained by trip members 95, 151, Fig. 2, the latter being moved to release the trip when a predetermined signal selects latch 157, which acts through a rod 163, Fig. 4. When so released, arm 97 rises sharply and operates a pawl co-operating with ratchet wheel 57 to move the platen the distance between two lines of printing. To ensure that line-spacing shall also be effected simultaneously and automatically when a carriage-returning signal is received, to avoid printing on top of words previously printed, a projection 101 on a rod 107 operated by the carriagereturning latch 159 engages a projection 162 on rod 163, which is thus moved to effect linespacing as described above. Platen-roller couplings; platen rotation, for blanking. Blanking is obtained by two carriagereturn signals in succession causing rotation of platen 32 through a greater distance than required for line-spacing, and is effected rapidly by gear wheels. When the carriage is in its returned position after the first signal it depresses a rod 90, Fig. 3, which slightly rotates the rod 107 operated by the carriage-return latch 159, so that the projection 101 comes opposite to a lever, not shown, adapted to release a trip mechanism 105, Fig. 5, on receipt of a second carriage-return signal. This allows spring 167 to move a clutch member 115 into engagement with a continuously driven member 116. Member 116 is driven through gear wheels 113, 111, 112, 165, 166, Figs. 4 and 5. Engagement of the clutch causes a single revolution of gear-wheel 110, from which the platen 32 is rotated through wheels 108, 109, and a stud 120 which snaps into a corresponding hole in the end disc 122 of the platen when the stud and hole register. The platen thus rotates to bring a fresh supply of paper to the correct printing position irrespective of the position of the platen at completion of the previous message. The machine may be used with paper from a supply roll or with cut forms. In the latter case the forms may be fed to the machine by the arrangement described in Specification 21055/14. A projection 123 throws the clutch out after one revolution, and resets the trip 105. A cam device 126 puts a. spring 117 under compression and its release aids rapid fixing of the clutch and arrest of the platen.